Methods of making coated articles by sputtering silver in oxygen inclusive atmosphere

ABSTRACT

A sputter coated article is provided with improved mechanical durability (e.g., pre-HT scratch resistance) and/or thermal stability by sputtering at least one Ag inclusive layer in an atmosphere including at least O 2  gas. For instance, in certain example embodiments an Ag inclusive target may be sputtered in an atmosphere including a combination of Ar and O 2  gas. In certain embodiments, this enables the resulting AgO x  infrared (IR) reflecting layer to better adhere to adjacent contact layer(s).

This application claims the benefit of Provisional Application No.60/407,687, filed Sep. 4, 2002, the entire content of which is herebyincorporated herein by reference.

This invention relates to heat treatable low emissivity (low-E) coatedarticles, and methods of making the same. Such coated articles may beused in the context of vehicle windshields, insulating glass (IG) units,other types of architectural and/or vehicle windows, and other suitableapplications.

BACKGROUND AND SUMMARY OF THE INVENTION

Layer coatings provided for solar management purposes are known in theart. Such coatings often seek to reflect significant amounts of infrared(IR) radiation while at the same time enabling a high amount of visiblelight transmittance. High visible transmittance is often desired, andthis need often conflicts with the need for good IR reflection, and itis difficult to obtain both simultaneously. It is also desirable forsuch coatings to be heat treatable in some instances, so that they maybe used in vehicle windows where heat bending is required, temperedarchitectural or vehicle windows, and/or the like.

WO 02/04375 discloses a low-E coating including the following layers:glass/TiO_(x)/Si_(x)N_(y)/NiCrO_(x)/Ag/NiCrO_(x)/SnO_(x)/Si_(x)N_(y)/NiCrO_(x)/Ag/NiCrO_(x)/SnO_(x)/Si_(x)N_(y).The metallic Ag layers are sputtered in an argon (Ar) gas atmosphere, asis typical in the art. This low-E coating provides for excellent solarperformance and is an overall good coating. However, it has been foundthat this coating is subject to scratching during, for example,pre-final-product processing (e.g., before heat treatment).

In view of the above, it will be apparent to those skilled in the artthat there exists a need in the art for a low-E coating that is moremechanically durable and thus less susceptible to scratching and thelike, and/or which is more thermally stable (i.e., does not suffer aradical drop in visible transmission upon heat treatment such astempering).

An object of certain example embodiments of this invention is to providea more durable coating that is less susceptible to scratching and/orother types of mechanical damage, and/or which has improved thermalstability.

Surprisingly, it has been found that sputtering the Ag inclusive layersof the aforesaid coating in an atmosphere not simply including Ar gas,but also including oxygen gas (O₂), renders the resulting coating (a)more mechanically durable and less susceptible to scratching, and/or (b)acceptably thermally stable. For example, it has been found thatsputtering at least one of the Ag inclusive layers of the aforesaidcoating in an atmosphere including a combination of Ar/O₂ gas leads to amore durable without sacrificing thermal stability.

U.S. Pat. No. 5,584,902 discloses a low-E coating system including, fromthe glass substrate outward, a stack of: Si₃N₄/NiCr/Ag/NiCr/Si₃N₄. Likemost other prior art, the Ag layer of the '902 patent is preferablysputtered in an Ar gas atmosphere (e.g., see col. 16, lines 33-45).However, the '902 Patent does mention at col. 12, lines 59-63, that eachof the three metallic layers NiCr/Ag/NiCr may be sputtered optionally inan atmosphere including “a small amount of O₂ (e.g. about 5-10%).”However, this means that all three layers (NiCr, Ag and NiCr) aresputtered in the same atmosphere, and that each atmosphere includes thesame amount of oxygen—this is undesirable in many instances. While the'902 coating is heat treatable and low-E in nature, it is characterizedby rather high emissivity and/or sheet resistance values which lead torather low R_(solar) (total solar energy reflectance) values around22-24%. For example, one coating reported in the '902 patent had a sheetresistance (R_(s)) of 14.4 ohms/square and a normal emissivity (E_(n))of 0.15 before heat treatment; and a R_(s) of 10.5 ohms/square and aE_(n) of 0.11 after heat treatment. Moreover, there is no disclosure orsuggestion in the '902 Patent that sputtering an Ag target in anatmosphere including oxygen can lead to improved mechanical durabilityand/or thermal stability.

As explained above, an object of certain embodiments of this inventionis to provide a more durable low-E coating that is less susceptible toscratching and/or other types of mechanical damage, and/or which hasimproved thermal stability. This object may be fulfilled by sputteringat least one Ag inclusive layer in an atmosphere including O₂ gas (e.g.,a combination of Ar and O₂ gas may be used). The use of oxygen gasproximate the Ag sputtering target is especially beneficial in thisrespect when one or more of the immediately adjacent contact layersis/are significantly oxidized (e.g., when one or both of the adjacentcontact layers comprises NiCrO_(x)).

Another object of certain exemplary embodiments of this invention is toprovide a dual silver low-E coating which is heat treatable and ismechanically and/or chemically durable.

Another object of certain exemplary embodiments of this invention is toprovide a heat treatable low-E coating having high visible transmittance(e.g., of at least about 65%) combined with a normal emissivity (E_(n))of no greater than 0.08 (more preferably no greater than 0.06) beforeheat treatment, and/or an E_(n) of no greater than 0.07 (more preferablyno greater than 0.05) after heat treatment (HT).

Another object of certain exemplary embodiments of this invention is toprovide a heat treatable low-E coating having high visible transmittancecombined with a sheet resistance (R_(s)) of no greater than 10.0ohms/sq. (more preferably no greater than 8.0 ohms/sq., and mostpreferably no greater than about 5.0 ohms/sq.) before heat treatment;and/or a R_(s) of no greater than 8.0 ohms/sq. (more preferably nogreater than 6.0 ohms/sq., and most preferably no greater than about 4.0ohms/sq.) after heat treatment.

Another object of this invention is to fulfill one or more of theabove-listed objects.

Generally speaking, certain example embodiments of this inventionfulfill one or more of the above-listed objects by providing a method ofmaking a coated article including a coating supported by a glasssubstrate, the method comprising: sputtering a first dielectric layer soas to be supported by the glass substrate; sputtering a first contactlayer on the substrate over the first dielectric layer; sputtering atarget comprising Ag in an atmosphere including at least oxygen gas inorder to form an infrared (IR) reflecting layer comprising AgO_(x) whichis located over and contacts the first contact layer; sputtering asecond contact layer on the substrate so that the second contact layeris located over and in contact with the IR reflecting layer comprisingAgO_(x); and wherein said sputtering of at least one of the contactlayers comprises sputtering a target comprising a metal or metal alloyin an atmosphere including at least oxygen gas in order to form a metaloxide contact layer, and wherein more oxygen gas is introduced into anatmosphere used in sputtering the metal oxide contact layer than isintroduced into an atmosphere proximate the target comprising Ag used insputtering the IR reflecting layer comprising AgO_(x). In one exampleembodiment, oxygen may be fed into the neighboring cathode bay insteadof directly into either the contact layer or IR reflecting layer bays;oxygen would thereby enter into the contact layer and/or IR reflectinglayer bay(s)s by diffusion.

Certain other example embodiments of this invention fulfill one or moreof the above-listed objects by providing a coated article including acoating supported by a glass substrate, the coating comprising: a firstdielectric layer supported by the glass substrate; a first contact layercomprising a metal oxide provided on the substrate over the firstdielectric layer, wherein a central portion of the first contact layeris at least about 40% oxidized; an IR reflecting layer comprisingAgO_(x) contacting the first contact layer, wherein the first contactlayer is either above or below the IR reflecting layer on the substrate;and at least one dielectric layer provided on the substrate over the IRreflecting layer and the first contact layer.

Certain other example embodiments of this invention fulfill one or moreof the above-listed objects by providing a coated article including acoating supported by a glass substrate, the coating comprising: a firstdielectric layer supported by the glass substrate; an optional firstcontact layer comprising a metal oxide provided on the substrate overthe first dielectric layer, wherein a portion of the first contact layeris at least about 40% oxidized; an IR reflecting layer comprisingAgO_(x) contacting the first contact layer or the bottom dielectriclayer, an optional contact layer above the IR reflecting layer; and atleast one dielectric layer provided on the substrate over the IRreflecting layer contacting directly either the IR reflecting layer orthe optional contact layer.

This invention will now be described with respect to certain exampleembodiments thereof as illustrated in the following drawings, wherein:

IN THE DRAWINGS

FIG. 1 is a side cross sectional view of a coated article according toan example embodiment of this invention.

FIG. 2 is a schematic partial cross sectional view of a laminatedvehicle windshield according to an example embodiment of this invention,in which coatings according to any embodiment of this invention may beused.

FIG. 3(a) is cross sectional view of a portion of a coating according toan optional embodiment of this invention illustrating a pair ofoxidation graded contact layers (e.g., NiCrO_(x) layers) surrounding anIR reflecting layer.

FIG. 3(b) is cross sectional view of a portion of a coating according toanother optional embodiment of this invention illustrating an IRreflecting layer surrounded by a pair of contact layers (e.g., NiCrO_(x)layers), only one of which is oxidation graded.

FIG. 4 is a schematic and partial cross sectional view illustrating howan optional graded contact layer (e.g., NiCrO_(x) layer) is depositedvia sputtering in accordance with an example embodiment of thisinvention.

FIG. 5 is a cross sectional view of the layer stack of a coatingaccording to an Example of the instant invention.

FIG. 6 is a cross sectional view of a coated article according toanother embodiment of this invention.

DETAILED DESCRIPTION OF CERTAIN EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts or layers throughout theseveral views.

Certain embodiments of this invention provide a low-E coating or layersystem that may be used in applications such as vehicle windshields,other vehicle windows, skylights, glass doors, IG units, other types ofarchitectural or residential windows, and the like. Coatings accordingto certain embodiments of this invention preferably have low-Echaracteristics as well as high visible transmittance, and are heattreatable. Preferably, coatings of certain embodiments herein aremechanically durable before and/or after heat treatment (HT), and HTdoes not cause a significant jump in sheet resistance (R_(s)) and/orhaze. As is known in the art, such HT often necessitates heating thecoated substrate to temperature(s) of from 560° C. to 800° C. for asufficient period of time to attain the desired result (e.g., tempering,bending, and/or heat strengthening).

Improved mechanical durability (e.g., pre-HT) is surprisingly achievedaccording to certain embodiments of this invention by sputtering atleast one Ag inclusive layer (9 and/or 19) in an atmosphere including atleast O₂ gas. For instance, in certain example embodiments an Aginclusive target may be sputtered in an atmosphere including acombination of Ar (or other inert) and O₂ gas. The result is a layer ofor including AgO_(x). The term “AgO_(x)” as used herein means that thelayer (9 and/or 19) including Ag is formed when at least some oxygen ispresent in a sputtering chamber in which an Ag inclusive target islocated so that the resulting layer is (a) at least partially oxidized,and/or (b) of or includes metallic Ag intermixed with oxygen atoms. Ithas surprisingly been found that the use of the oxygen in the Agsputtering chamber improves the adhesion between the AgO_(x) layer (9and/or 19) and at least one of the immediately adjacent contact layers(7, 11, 17 and/or 21) (e.g., a contact layer may be of or includeNiCrO_(x), or any other suitable material, so long as it contacts thelayer including Ag). This benefit of using oxygen in the Ag sputteringchamber has been found to be particularly advantageous when the contactlayer(s) (7, 11, 17 and/or 21) is significantly oxidized; i.e., thecentral portion of the contact layer(s) is at least partially oxidized,and at least some part of the contact layer is at least about 40%oxidized, more preferably at least about 50% oxidized, and mostpreferably at least about 60% oxidized. In certain embodiments, visibletransmission of the coated article does not decrease upon heat treatmentfor thermal tempering or the like. In certain embodiments, transmissionstarts low (e.g., at 60-65%, such as 63%) and then increases uponheating from about 1-10%.

FIG. 1 is a side cross sectional view of a coated article according toan embodiment of this invention. The coated article includes substrate 1(e.g., clear, green, bronze, or blue-green glass substrate from about1.0 to 10.0 mm thick, more preferably from about 1.8 mm to 4 mm thick),first dielectric anti-reflection layer 3, second dielectric layer 5,first lower contact layer 7 (which contacts layer 9), first AgO_(x)conductive infrared (IR) reflecting layer 9, first upper contact layer11 (which contacts AgO_(x) layer 9), third dielectric layer 13 (whichmay be deposited in one or multiple steps in different embodiments ofthis invention), fourth dielectric layer 15, second lower contact layer17 (which contacts layer 19), second AgO_(x) or Ag conductive IRreflecting layer 19, second upper contact layer 21 (which contacts layer19), fifth dielectric layer 23, and finally sixth protective dielectriclayer 25. The “contact” layers each contact at least one IR reflectinglayer 9 or 19. The aforesaid layers 3-25 make up heat treatable low-E(i.e., low emissivity) coating 27 which is provided on glass or plasticsubstrate 1.

In certain embodiments of this invention, first dielectric layer 3 maybe of or include titanium dioxide (TiO_(x) where x is from 1.7 to 2.3,most preferably 2.0), silicon nitride (Si_(x)N_(y) where x/y may beabout 0.75 (i.e., Si₃N₄), or alternatively x/y may be from about 0.76 to1.5 in Si-rich embodiments), silicon dioxide (SiO_(x) where x is from1.7 to 2.3, most preferably about 2.0), niobium oxide (e.g., Nb₂O₅),SiZrN, tin oxide, zinc oxide, silicon oxynitride, or any other suitabledielectric material. First dielectric layer 3 functions as anantireflection layer in certain embodiments of this invention.

Second dielectric layer 5 may function to reduce haze in certainembodiments of this invention, and is preferably of or includes siliconnitride (e.g., Si₃N₄, or alternatively silicon-rich silicon nitrideSi_(x)N_(y) where x/y is from 0.76 to 1.5, more preferably from 0.85 to1.2, for haze reduction purposes). When sputtering silicon nitridelayer(s) herein, a Si target may be used, or alternative a targetincluding Si admixed with up to 3-20% by weight aluminum and/orstainless steel (e.g. SS#316) may be used, with about this amount ofaluminum and/or steel then appearing in the layer(s) so formed. Othermaterials may also be used for haze reducing layer 5, including but notlimited to SiZrN.

Infrared (IR) reflecting layer 9 and 19 preferably include silver (Ag)as an IR reflecting material. One or both of IR reflecting layers 9, 19may be of or include AgO_(x) as described above (e.g., formed bysputtering Ag target in an oxygen inclusive atmosphere). When only oneof layer 9 and 19 is of or includes AgO_(x), the other IR reflectinglayer may be of or include Ag or any other suitable IR reflectingmaterial. These IR reflecting layers 9, 19 help enable coating 27 tohave low-E characteristics.

Contact layers 7, 11, 17, and 21 are of or include nickel (Ni) oxide, ora nickel alloy oxide such as nickel chrome oxide (NiCrO_(x)), in certainembodiments of this invention. NiCrO_(x) layers 7, 11, 17, and/or 21 maybe fully oxidized in certain embodiments of this invention (i.e., fullystochiometric), or may be at least about 75% oxidized in otherembodiments of this invention. While NiCrO_(x) is a preferred materialfor layers 7, 11, 17 and/or 21, those skilled in the art will recognizedthat other materials may instead be used and that one or more of thecontact layers may be a metal oxide such as oxides of Ni, oxides of Nialloys, oxides of Cr, oxides of Cr alloys, NiCrO_(x)N_(y), or any othersuitable material. Thus, when it is said that a contact layer is a“metal oxide”, this includes oxides of metal alloys such as niCr andalso includes layers that may be partially nitrided in addition tooxided. Optionally, one or both contact layers may be removed adjacentone or both IR reflecting layers.

In any event, regardless of what metal(s) is provided in contactlayer(s) 7, 11, 17 and 21, the benefit of using oxygen in an Agsputtering chamber(s) has been found to be particularly advantageouswhen one or more of the contact layer(s) (7, 11, 17 and/or 21) locatedadjacent an AgO_(x) layer (9 or 19) is significantly oxidized. Thus, atleast one contact layer (and preferably two) located adjacent an AgO_(x)layer has a central portion that is at least partially oxidized, and atleast some part of the contact layer is at least about 40% oxidized,more preferably at least about 50% oxidized, and most preferably atleast about 60% oxidized. It is noted that contact layers 7, 11, 17and/or 21 may or may not be continuous in different embodiments of thisinvention.

When layers 7, 11, 17 and/or 21 comprise NiCrO_(x) in certainembodiments, the Ni and Cr may be provided in different amounts, such asin the form of nichrome by weight about 0-90% Ni and 10-90% Cr. Anexemplary sputtering target for depositing these layers includes notonly SS-316 which consists essentially of 10% Ni and 90% otheringredients, mainly Fe and Cr, but Haynes 214 alloy as well.

One or more of contact layers 7, 11, 17, and/or 21 (e.g., of orincluding NiCrO_(x)) may be oxidation graded in certain embodiments ofthis invention so that the degree of oxidation in the layer(s) changesthroughout the thickness of the layer(s). Oxidation grading is optional,and need not be provided in certain embodiments of this invention. Whenoxidation grading is practiced, one or more of contact layers (7, 11, 17and/or 21) may be graded so as to be less oxidized at the contactinterface with the immediately adjacent IR reflecting layer (9 or 19)than at a portion of the contact layer(s) further or more/most distantfrom the immediately adjacent IR reflecting layer (a central portion ofthe contact layer is at least partially oxidized in any event). It isbelieved that oxidation grading of one or more of contact layer(s) 7,11, 17 and/or 21 may help the low-E coating 27 to achieve thecombination of heat treatability and high visible transmission.

FIGS. 3(a) and 3(b) illustrate various types of oxidation grading of thecontact layer(s) according to certain example embodiments of this inventon. These figures are for purposes of example only. Further details withrespect to oxidation grading of the contact layer(s) may be found inU.S. Ser. No. 09/794,214, filed Feb. 28, 2001 (now U.S. Pat. No.6,576,349), the entire disclosure of which is hereby incorporated hereinby reference.

FIG. 4 illustrates how an oxidation graded contact layer may bedeposited on a substrate as part of a coating according to an exemplaryembodiment of this invention, using an asymmetric introduction of oxygengas at a target area. Substrate 1 with part of a layer system thereonproceeds in direction D through the sputter coater. When the substrate 1is moving in direction D beneath target 51 (within shield 53), gas isintroduced around the target on two sides 57 and 59 thereof. On one side57 of target 51, at least oxygen (e.g., O₂) gas (e.g., oxygen flow ofabout 30-60 mL/min. at 4.1 kW), and optionally a mixture of oxygen andan inert gas such as argon (Ar), is fed into the coating zone beneathand/or proximate the target. However, on the other side 59 of target 51,less oxygen gas is used and more of another gas such as Ar is introducedinto the coating zone beneath and/or proximate the target. Again,further details with respect to oxidation grading may be found in U.S.Ser. No. 09/794,224 (now U.S. Patent No. 6.576,349). It can also be seenthat oxygen gas is used proximate the silver target 60 as discussedherein.

Turning back to FIG. 1, third dielectric layer 13 acts as a couplinglayer between the two halves of the coating 27, and is of or includestin oxide in certain embodiments of this invention. However, otherdielectric materials may instead be used for layer 13, including but notlimited to silicon nitride, titanium dioxide, niobium oxide, siliconoxynitride, zinc oxide, or the like. Fourth dielectric layer 15functions as a haze reducer in certain embodiments of this invention,and is preferably of or includes silicon nitride (e.g., Si₃N₄, oralternatively silicon-rich silicon nitride discussed above). However, inalternative embodiments of this invention, other materials (e.g., SiZrN)may instead be used for dielectric layer 15.

Fifth dielectric layer 23 may be of or include tin oxide in certainembodiments of this invention. However, other dielectric materials mayinstead be used for layer 23, including but not limited to siliconnitride, titanium dioxide, niobium oxide, silicon oxynitride, zincoxide, or the like. Protective overcoat dielectric layer 25 is providedat least for durability purposes, and may be of or include siliconnitride (e.g., Si₃N₄) in certain embodiments of this invention. However,other dielectric materials may instead be used for layer 25, includingbut not limited to titanium dioxide, silicon oxynitride, tin oxide, zincoxide, niobium oxide, SiZrN, or the like.

Other layer(s) below or above the illustrated coating 27 may also beprovided. Thus, while the layer system or coating 27 is “on” or“supported by” substrate 1 (directly or indirectly), other layer(s) maybe provided therebetween. Thus, for example, coating 27 of FIG. 1 may beconsidered “on” and “supported by” the substrate 1 even if otherlayer(s) are provided between layer 3 and substrate 1. Moreover, certainlayers of coating 27 may be removed in certain embodiments, while othersmay be added in other embodiments of this invention without departingfrom the overall spirit of certain embodiments of this invention.

Further details regarding the aforesaid layers 3-7, 11-17 and 21-25 maybe found in U.S. Ser. No. 09/794,224, filed Feb. 28, 2001 (now U.S.Patent No. 6,576,349), the entire disclosure of which is herebyincorporated herein y reference (see also WO 02/04375).

FIG. 2 illustrates a laminate (e.g., vehicle windshield) according to anembodiment of this invention, including coating 27 of FIG. 1. As shownin FIG. 2, the laminate (e.g., windshield) includes first glasssubstrate 1 on which coating 27 is provided, and second glass substrate31. PVB (or other polymer inclusive material) layer 33 is providedbetween the substrates in a known manner, so as to contact coating 27 onone side thereof. In the FIG. 2 embodiment, coating 27 is provided at/onthe second (or #2) surface 37 of the laminate. The first surface 35 isat the exterior of the laminate exposed to the outside of the vehicle,second surface 37 is on the interior or inside of outer substrate 1third surface 39 is on the inside of the interior substrate 31, andfourth surface 41 is at the interior of the vehicle. Coatings 27 hereinare preferably provided on either the second 37 or third 39 surface(s)of such laminates (the same is also true with regard to IG units).

Turning back to FIG. 1, while various thicknesses may be used consistentwith one or more of the objects discussed herein, exemplary preferredthicknesses and example materials for the respective layers on the glasssubstrate 1 in the FIG. 1 embodiment are as follows:

TABLE 1 (Example Materials/Thicknesses; FIG. 1 Embodiment) PreferredMore Layer Range (Å) Preferred (Å) Example TiO_(x) (layer 3) 0-400 Å40-200 Å  80 Å Si_(x)N_(y) (layer 5) 0-400 Å 50-250 Å 165 Å NiCrO_(x)(layer 7) 5-100 Å 10-50 Å  26 Å AgO_(x) (layer 9) 50-250 Å 80-120 Å 103Å NiCrO_(x) (layer 11) 5-100 Å 10-50 Å  26 Å SnO₂ (layer 13) 0-800 Å450-800 Å 550 Å Si_(x)N_(y) (layer 15) 0-800 Å 50-250 Å 165 Å NiCrO_(x)(layer 17) 5-100 Å 10-50 Å  26 Å Ag (layer 19) 50-250 Å 80-150 Å 130 ÅNiCrO_(x) (layer 21) 5-100 Å 10-50 Å  26 Å SnO₂ (layer 23) 0-500 Å50-250 Å 100 Å Si₃N₄ (layer 25) 0-500 Å 100-300 Å 205 Å

FIG. 6 illustrates a low-E heat treatable coating 27 according toanother embodiment of this invention. The FIG. 6 coating 27 is the sameas the FIG. 1 coating described above, except that either (i) dielectriclayer 3 is removed, or (ii) layers 3 and 5 are replaced with a singlesilicon nitride layer 40. Silicon nitride layer 40 may be of or includeSi₃N₄ in certain embodiments of this invention. In other embodiments,silicon nitride layer 40 may be of or include Si_(x)N_(y) where x/y maybe from about 0.65 to 0.80, or alternatively from about 0.76 to 1.5 insilicon rich embodiments. In another embodiment of the particular FIG. 6embodiment, layer 40 may be of or include SiZrN. Nitride layer 40 isadvantageous because if functions to reduce haze, and is preferably fromabout 10 to 500 Å thick, more preferably from about 200-400 Å thick. Aswith all embodiments herein, Si-rich silicon nitride has improvedperformance in reducing haze compared to Si₃N₄.

In certain exemplary embodiments of this invention, coating/layersystems 27 have the following low-E characteristics before/after heattreatment (HT) when in monolithic form, as set forth in Table 2:

TABLE 2 Monolithic Before/After Heat Treatment (HT) More MostCharacteristic General Preferred Preferred R_(s) (ohms/sq.)(before HT):<=10.0  <=8.0 <=5.0 R_(s) (ohms/sq.)(after HT): <=8.0 <=6.0 <=4.0 E_(n)(before HT):  <=0.08  <=0.06 n/a E_(n) (after HT):  <=0.07  <=0.05 n/aT_(vis) (pre and post-HT):   >=60%    >=70%    >=75%  Haze (after HT): <=0.40  <=0.30  <=0.28

As can be seen above, in certain embodiments of this invention wherecoated articles are used monolithically, they have a high visibletransmittance both before and after HT.

Coatings 27 according to certain exemplary embodiments of this invention(e.g., FIGS. 1-6) have the following color/transmission/reflection/hazecharacteristics when on a clear soda lime silica glass substrate (e.g.,2-4 mm thick) in laminated or IG unit form with another similar clearsoda lime silica glass substrate (e.g., in laminated form of a vehiclewindshield with PVB or index oil between the two substrates as shown inFIG. 2, or in conventional IG unit form) as set forth in Table 3. InTable 3 below, R_(g)Y is visible reflection from the exterior of thevehicle/building as shown in FIG. 2, and R_(f)Y is visible reflectionfrom the other side of the laminate such as from the vehicle/buildinginterior in FIG. 2, and the a*, b* values under these respectivereflection parameters also correspond to glass (g) side and film (f)side, respectively.

TABLE 3 Color/Transmission After HT; Laminated or IG Unit FormCharacteristic General More Preferred T_(vis) (Ill. A, 2 deg.):   >=60%   >=70%  T_(vis) (Ill. C, 2 deg.):   >=60%    >=70%  R_(g)Y (Ill. A, C;2 deg.):   <=13%    <=11%  a*_(g) (Ill. C; 2°): −3.0 to +5.0 −2.0 to+2.0 b*_(g) (Ill. C; 2°): −10.0 to +10.0 −8.0 to −2.0 R_(f)Y (Ill. A, C;2 deg.):   <=14%    <=12%  a*_(f) (Ill. C; 2°): −5.0 to +5.0 −2.0 to2.0   b*_(f) (Ill. C; 2°): −10.0 to 10.0   −5.0 to 5.0   R_(solar):  >=26%    >=28%  Haze: <=0.4 <=0.3 T_(solar):   <=50%    <=48% T_(ultraviolet)  <=0.45  <=0.36 SHGC:  <=0.50  <=0.40

EXAMPLE

The following coating was made in accordance with an example embodimentof this invention (e.g., see FIG. 5); this example being provided forpurposes of example but without limitation. The coating/layer system 27shown in FIG. 5 is considered on a clear 3.3 mm thick large soda limesilica float glass substrate 1. A Leybold Terra-G seven-chamber sputtercoating apparatus was used to sputter the coatings 27 onto thesubstrates 1. There was a total of 27 cathodes used. Cathode numberingutilizes the first digit to refer to the coater chamber, and the seconddigit to refer to the cathode position in that chamber. For example,cathode #32 was the second cathode (second digit) in the third (firstdigit) sputter chamber. Thus, it can be seen for example that thecathodes used for sputtering the Ag inclusive layers (i.e., cathodes 31,32 and 62, 63) are in different sputtering chambers than the cathodesused for sputtering the NiCrO_(x) contact layers (i.e., cathodes 25, 33,61 and 64). Below, “*” means Al content of approximately 10%. The linespeed was about 4.99 meters per minute, and the coater/process setup isset forth in Table 4. All gas flows (e.g., oxygen, argon, nitrogen) arepresented in units of sccm. Volts refers to cathode volts, and amps (A)refers to cathode amps. Pressure is measured in hecta pascals. Trim gasrefers to individually adjusted gas flows along the cathode length tomake corrections regarding layer thickness or stoichiometry uniformity,and the flow units are in terms of sccm. The NiCr targets wereapproximately 80/20 NiCr. The pressure for each sputter chamber was from3.7 to 7 E-3 hPa.

TABLE 4 Coater Setup/Processes for Example Cathode Target Volts (V)Power (kW) Ar (sccm) O₂ (sccm) N₂ (sccm) Trim Gas #11 Ti 552 12.9 350 110 29.7 O₂ #12 Ti 549 40.8 350 11 0 29.8 O₂ #13 Ti 534 0.6 350 11 0 29.8O₂ #14 Ti 263 39.2 350 11 0 29.8 O₂ #15 Ti 25 0 350 0 0 0 #23 Si* 65871.7 250 0 299  124 N₂ #25 NiCr 507 18 250 193 0 0 #31 Ag n/a n/a 250 00 0 #32 Ag n/a n/a 225 30 0 0 #33 NiCr 479 13.5 250 72 0 0 #35 Sn 10.3 0225 72 0 0 #41 Sn 479.5 33.8 200 389 75  159 O₂ #42 Sn 480 33.2 200 36075  166 O₂ #43 Sn 494 30.5 200 360 75  166 O₂ #44 Sn 472 33.9 200 360 75 166 O₂ #45 Sn 477 31.1 200 360 75  166 O₂ #51 Sn 243 40.6 200 389 75 166 O₂ #52 Sn 2.1 0 200 0 75 0 #54 Si* 651 56 250 0 280  124 N₂ #61NiCr 507 18 250 128 0 0 #62 Ag n/a n/a 275 0 0 0 #63 Ag 473 8 300 0 0 0#64 NiCr 499 13.4 250 59 0 0 #71 Sn 505.6 42 200 555 62  195 O₂ #73 Si*488 61 250 0 500  220 N₂ #74 Si* 498 61 250 0 500  220 N₂ #75 Si* 497 61250 0 500  220 N₂

In view of the coater set-up set forth above, it can be seen that thelower IR reflecting layer 9 was sputtered in an atmosphere includingoxygen, but that the upper IR reflecting layer 19 (see cathode #s 62-63)was sputtered in a purely Ar atmosphere. Thus, lower IR reflecting layer9 (see cathode #s 31-32) was of or included AgO_(x) while the upper IRreflecting layer 19 was metallic Ag. In other example embodiments ofthis invention, both layers 9, 19 (or alternatively just upper IRreflecting layer 19) may be of or include AgO_(x). The coating from theExample above was characterized by solar/optical/thicknesscharacteristics as set forth in Tables 1-3 above.

With respect to the lower IR reflecting layer 9 where both oxygen andargon gas is used in sputtering the Ag target, it can be seen that moreoxygen gas may be introduced into the respective atmospheres proximatethe targets used in sputtering the first and second contact layers (7,11) (or in an intermediate unused bay/chamber) than is introduced intothe atmosphere proximate the target comprising Ag used in sputtering theIR reflecting layer comprising AgO_(x) (9). In the Example above, 30sccm of oxygen gas is introduced into the atmosphere proximate one ofthe Ag targets, while 193 sccm and 72 sccm of oxygen are introduced intothe respective atmospheres used for sputtering the adjacent metal oxidecontact layers 7 and 11, respectively. Thus, the respective contactlayers 7 and 11 may be oxidized to a greater extent than is IRreflecting layer 9. The relative oxidation of a layer is complexfunction of the sputtering process parameters. We could therefore havesituations where the relative oxidation of the contact layers versus theadjacent IR reflecting layer may not be directly correlated to therelative oxygen gas flows in the respective bays. The scope of theinvention is not limited to the relative oxidation levels between thecontact (or dielectric) layers and the IR reflecting layers, unlessrecited in the claims.

In certain embodiments of this invention, the ratio of (a) oxygen gasintroduced into the atmosphere proximate the Ag inclusive target forsputtering the IR reflecting layer, to (b) oxygen gas introduced intothe atmosphere proximate a target for sputtering an adjacent contactlayer, is from about 1:1.3 to 1:10, more preferably from about 1:1.5 to1:8, and most preferably from about 1:2 to 1:5. In different embodimentsof this invention, from about 10-250 sccm of oxygen gas may beintroduced into the atmosphere proximate the Ag inclusive target, morepreferably from about 20-100 sccm, and most preferably from about 20-60sccm (e.g., regardless of the relative oxygen flow in neighboringcathode bays or the oxidation levels of the adjacent layers in thestack). Additionally, the oxygen for the contact layer(s) and/or theadjacent IR reflecting layer may be supplied in total or in part fromadjacent bays. In this manner, we would rely on diffusion in the coaterto supply oxygen to the contact layer(s) and/or the IR reflectinglayer(s).

After being made, the coated article of the aforesaid Example was heattreated (HT) in order to temper the same. Surprisingly, it was foundthat high visible transmission (at least about 65%, more preferably atleast about 70%, and most preferably at least about 75%) was able to bemaintained for longer periods of HT when the oxygen was provided in theAg target atmosphere for at least one of the Ag inclusive layers. Thetempered coated article may then be used either monolithically, or incombination with another substrate, in various window applications.

Certain terms are prevalently used in the glass coating art,particularly when defining the properties and solar managementcharacteristics of coated glass. Such terms are used herein inaccordance with their well known meaning. For example, see the meaningsof these terms as set forth in 09/794,224 now U.S. Patent No. 6,576,349incorporated herein by reference (see also WO 02/04375)

Once given the above disclosure many other features, modifications andimprovements will become apparent to the skilled artisan. For example,and without limitation, the use of oxygen in sputtering an Ag inclusivelayer may be used with or without oxidation graded contact layer(s)and/or Si-rich silicon nitride layer(s), and may be used with singlesilver layer stacks, as well as the illustrated dual (or more) silverlayer stacks. Furthermore, the dielectric materials listed above for thedielectric layers are provided for purposes of example and the instantinvention is not so limited unless such materials are recited in theclaims. Moreover, the term “sputtering” as used herein includes any andall forms of sputtering including but not limited to magnetronsputtering, ion-assisted sputtering, etc. Such other features,modifications and improvements are therefore considered to be a part ofthis invention, the scope of which is to be determined by the followingclaims:

What is claimed is:
 1. A method of making a coated article including acoating supported by a glass substrate, the method comprising:sputtering a first dielectric layer on the glass substrate; sputtering atarget comprising a metal or metal alloy in an atmosphere including atleast oxygen gas in order to form a first contact layer comprising ametal oxide on the substrate over the first dielectric layer; sputteringa target comprising Ag in an atmosphere including at least oxygen gas inorder to form an infrared (IR) reflecting layer comprising AgO_(x) whichis located over and contacts the first contact layer; sputtering atarget comprising a metal or metal alloy in an atmosphere including atleast oxygen gas in order to form a second contact layer comprising ametal oxide on the substrate so that the second contact layer is locatedover and in contact with the IR reflecting layer comprising AgO_(x);wherein more oxygen gas is introduced into each of the respectiveatmospheres proximate the targets used in sputtering the first andsecond contact layer than is introduced into the atmosphere proximatethe target comprising Ag used in sputtering the IR reflecting layercomprising AgO_(x); and heat treating the glass substrate with thecoating thereon in order to thermally temper the same, and whereinvisible transmission of the coated article does not decrease as a resultof said heat treating.
 2. The method of claim 1, wherein a ratio of (a)oxygen gas introduced into the atmosphere proximate the targetcomprising Ag for sputtering the IR reflecting layer, to (b) oxygen gasintroduced into the atmosphere proximate one of the targets forsputtering a corresponding one of the contact layers, is from about1:1.3 to 1:10; so that more oxygen is present proximate the target usedin sputtering the contact layer than is present proximate the targetcomprising Ag used in sputtering the IR reflecting layer.
 3. The methodof claim 2, wherein the ratio is from about 1:1.5 to 1:8.
 4. The methodof claim 2, wherein the ratio is from about 1:2 to 1:5.
 5. The method ofclaim 1, wherein from about 20-100 sccm of oxygen gas is introduced intothe atmosphere proximate the target comprising Ag, and wherein at leastone of the contact layers comprises NiCrO_(x).
 6. The method of claim 1,wherein from about 20-60 sccm of oxygen gas is introduced into theatmosphere proximate the target comprising Ag.
 7. The method of claim 1,wherein both the oxygen gas and argon gas are introduced into theatmosphere proximate the target comprising Ag, and wherein more argongas than oxygen gas is introduced into the atmosphere proximate thetarget comprising Ag.
 8. The method of claim 1, wherein at least one ofthe contact layers comprises NiCrO_(x) and is oxidation graded so that afirst portion of said one contact layer close to said infrared (IR)reflecting layer is less oxidized than a second portion of said onecontact layer that is further from said infrared (IR) reflecting layerand is located in a central portion of said one contact layer.
 9. Themethod of claim 1, wherein the coated article comprises from the glasssubstrate outwardly: the first dielectric layer; the first contact layerwhich comprises NiCrO_(x); the IR reflecting layer comprising AgO_(x);the second contact layer which comprises NiCrO_(x); at least oneadditional dielectric layer; a third layer comprising NiCrO_(x); asecond IR reflecting layer; a fourth layer comprising NiCrO_(x); and atleast one additional dielectric layer.
 10. The method of claim 1,wherein the coated article as a visible transmittance of at least about65%, and a sheet resistance (Re) of no greater than 8.0 ohms/sq.
 11. Themethod of claim 1, wherein at least one of the contact layers comprisesNiCrO_(x).
 12. The method of claim 1, wherein another dielectric layeris located between the first dielectric layer and the first contactlayer.
 13. The method of claim 12, wherein said another dielectric layercomprises silicon nitride, and the first dielectric layer comprises anoxide of titanium.
 14. A method of making a coated article including acoating supported by a glass substrate, the method comprising:sputtering a first dielectric layer so as to be supported by the glasssubstrate; sputtering a first contact layer on the substrate over thefirst dielectric layer; sputtering a target comprising Ag in anatmosphere including at least oxygen gas in order to form an infrared(IR) reflecting layer comprising AgO_(x) which is located over andcontacts the first contact layer; sputtering a second contact layer onthe substrate so that the second contact layer is located over and incontact with the IR reflecting layer comprising AgO_(x); wherein saidsputtering of at least one of the contact layers comprises sputtering atarget comprising a metal or metal alloy in an atmosphere including atleast oxygen gas in order to form a metal oxide contact layer; heattreating the substrate with the coating thereon for tempering, andwherein visible transmission of the coated article does not decrease dueto the heat treating; wherein more oxygen gas is provided in anatmosphere used in sputtering the metal oxide contact layer than isprovided in an atmosphere proximate target comprising Ag used insputtering the IR reflecting layer comprising AgO_(x); and whereinvisible transmission of the coated article increased upon said heattreating.
 15. The method of claim 14, wherein the first and secondcontact layers each comprise an oxide of NiCr.
 16. The method of claim14, wherein a ratio of (a) oxygen as introduced into the atmosphereproximate the target comprising Ag for sputtering the IR reflectinglayer, to (b) oxygen gas introduced into the atmosphere proximate one ofthe targets for sputtering a corresponding one of the contact layers, isfrom about 1:1.3 to 1:10; so that more oxygen is present proximate thetarget used in sputtering the contact layer than is present proximatethe target comprising Ag used in sputtering the IR reflecting layer. 17.The method of claim 16, wherein the ratio is from about 1:1.5 to 1:8.18. The method of claim 14, wherein from about 20-100 sccm of oxygen gasis introduced into the atmosphere proximate the target comprising Ag,and wherein at least one of the contact layers comprises an oxide ofNiCr.
 19. The method of claim 14, wherein from about 20-60 sccm ofoxygen gas is introduced into the atmosphere proximate the targetcomprising Ag.
 20. A method of making a coated article including acoating supported by a glass substrate, the method comprising:sputtering a first dielectric layer so as to be supported by at leastthe glass substrate; sputtering a first contact layer on the substrateover the first dielectric layer; sputtering a target comprising Ag in anatmosphere including at least oxygen gas in order to form an infrared(IR) reflecting layer comprising AgO_(x) which is located over andcontacts the first contact layer; sputtering a second contact layer onthe substrate so that the second contact layer is located over and incontact with the JR reflecting layer comprising AgO_(x); wherein saidsputtering of at least one of the contact layers comprises sputtering atarget comprising a metal or metal alloy in an atmosphere including atleast oxygen gas in order to form a metal oxide contact layer, whereinmore oxygen gas is provided in an atmosphere used in sputtering themetal oxide contact layer than is provided in an atmosphere proximatethe target comprising Ag used in sputtering the IR reflecting layercomprising AgO_(x).
 21. The method of claim 20, wherein the first andsecond contact layers each comprise an oxide of NiCr.
 22. The method ofclaim 20, wherein a ratio of (a) oxygen as introduced into theatmosphere proximate the target comprising Ag for sputtering the IRreflecting layer, to (b) oxygen gas introduced into the atmosphereproximate one of the targets for sputtering a corresponding one of thecontact layers, is from about 1:1.3 to 1:10; so that more oxygen ispresent proximate the target used in sputtering the contact layer thanis present proximate the target comprising Ag used in sputtering the IRreflecting layer.
 23. The method of claim 22, wherein the ratio is fromabout 1:1.5 to 1:8.
 24. The method of claim 20, wherein from about20-100 sccm of oxygen gas is introduced into the atmosphere proximatethe target comprising Ag, and wherein at least one of the contact layerscomprises an oxide of NiCr.
 25. The method of claim 20, wherein fromabout 20-60 sccm of oxygen gas is introduced into the atmosphereproximate the target comprising Ag.